The long-term goal of the project is the identification of genes that contribute to the overall genetic risk in bipolar disorder and the characterization of the biological function of these genes. It is anticipated that improvements in treatment, diagnosis and possibly prevention will evolve once genetic contributions to affective disorders are established. At present, the NIMH-IRP site is functioning primarily to collect additional affected bipolar sib pairs to enlarge the overall sample available to the NIMH grant-funded Bipolar Genetics consortium. The NIMH-IRP site has now enrolled and completely ascertained a total of 77 BP sibling pairs and their families (more than any other of the ten nationwide sites in the Consortium). The total number of probands and family members evaluated by our site is 349. 331 blood samples have been submitted for DNA analysis. Other families are in varying stages of completing the protocol requirements. Much of the interview and DNA collection work in the past year was devoted to the families of probands who entered this study previously. The completion of the first genome scan on multiplex families with bipolar affective disorder by our consortium provided evidence for susceptibility regions on 13q32, 1q32 and 18p11.2. Additional findings were published recently. Interestingly, some of these regions overlap with proposed chromosomal areas containing predisposing loci for schizophrenia. These results raise the possibility that schizophrenia and affective disorders share some susceptibility loci. Identifying candidate gene (genes localized in susceptibility regions) will require use of developing genetic technologies.